Vibration isolation system for marine vessels

ABSTRACT

A marine propulsion support system incorporates a vibration isolation structure which comprises a plurality of elastomeric support components, or mounts. The vibration isolation structure is disposed between a marine vessel and a propulsion drive mounting transom to which a marine propulsion component, such as an outboard motor, can be attached. Support of the propulsion drive mounting transom by the marine vessel extends through the vibration isolation structure so that elastomeric portions of the elastomeric support components can damp any vibration emanating from a marine propulsion device, such as an outboard motor, and a deck of a pontoon boat or other marine vessel.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally related to a vibration isolation system for marine vessels and, more particularly, to a vibration isolation system for use with pontoon boats having a marine propulsion device support pod attached below a deck of the pontoon boat.

2. Description of the Related Art

Many different designs are well known to those skilled in the art of pontoon boats. Typically, a marine propulsion device, such as an outboard motor, is attached to a support transom that is a portion of a pod, or scoop, that is attached below an undersurface of a deck of the pontoon boat. The outboard motor is generally mounted at a rearward location behind the deck and, in some cases, below the deck surface. The attachment is often to a transom portion of a pod that is suspended below the deck. This allows an outboard motor to be attached to the transom support plate in a manner that is generally similar to the way in which an outboard motor is attached to the transom of a boat that is not a pontoon boat.

One disadvantageous characteristic of many pontoon boats is that the large deck structure, in combination with the pontoon and other framework of the pontoon boat, amplifies vibration and noise emanating from the outboard motor attached to a rearward part of the pontoon boat. Vibration of the deck structure and its related hardware, such as railings, benches, seats, and gates, amplifies the noise resulting from the outboard motor vibrations.

U.S. Pat. No. 2,950,699, which issued to Ogden et al. on Aug. 30, 1960, describes a pontoon boat. The type of pontoon boat described is a dual pontoon with a flat deck that is adaptable to serve with satisfaction the needs of a slow moving bank fisherman, an urban dweller who chooses to seek privacy and complete relaxation in a cover in rivers or lakes, the family man who values safety and stability when he takes his family on an outing or picnic, the sportsman who wishes to indulge in water sports where speed and maneuverability are necessary, and the traveler who wants to move long distances quickly.

U.S. Pat. No. 3,210,783, which issued to Petty on Oct. 12, 1965, describes a water vehicle and, more particularly, pontoon boats or catamarans which are provided with an adjustable mount for an outboard mount to propel the vehicle through water and/or with a wheel mechanism movable to an operative position in which it is capable of supporting the vehicle for towing on land and to a retracted or inoperative position in which it offers minimum resistance to propulsion of the vehicle through water.

U.S. Pat. No. 3,289,226, which issued to Thompson on Dec. 6, 1996, describes a pontoon boat of the catamaran type with pontoons laterally spaced apart and supporting a substantially flat deck structure. A single outboard motor is disposed centrally of the stern for efficient driving of the boat at relatively high speeds.

U.S. Pat. No. 4,348,977, which issued to Okajima on Sep. 14, 1982, describes a water conveyance having two hull members spaced from each other and carrying a hydrofoil toward the stern thereof and an airfoil or wing toward the bow. The hydrofoil and airfoil cooperate to lift the hull members from the water to reduce water resistance and increase travel speed.

U.S. Pat. No. 4,870,919, which issued to Allison on Oct. 3, 1989, describes a catamaran type boat which comprises two pontoons which are rigidly interconnected in laterally spaced relationship by a plurality of transverse beams. An air guiding sheet is rigidly connected to the bottom surfaces of the transverse beams and defines an air tunnel extending above the water between the two pontoons.

U.S. Pat. No. 5,041,032, which issued to Makihara et al. on Aug. 20, 1991, describes a stern bracket for supporting an outboard motor of a boat. The stern bracket is fixed to a transom of the boat. The stern bracket is U-shaped and has a flat bottom and left and right side walls extending upwardly from left and right ends of the bottom. Each side wall includes a slant section and a vertical section extending upwardly from an upper end of the slant section.

U.S. Pat. No. 5,259,331, which issued to Hagan on Nov. 9, 1993, describes a motor pod for a pontoon boat. The pontoon boat is adapted to be propelled by an outboard motor. The boat has a deck and a pair of longitudinally extending parallel spaced apart pontoons depending from the deck and a means for mounting the outboard motor to the boat. The mounting means depends from the deck between the pontoons and comprises a pair of elongated substantially vertical spaced apart side walls having front and aft ends. The side walls become deeper and more spaced apart as they extend from their front ends to their aft ends. A substantially vertical and laterally extending transom is positioned between the side walls at the aft ends thereof and a bottom portion.

U.S. Pat. No. 5,846,106, which issued to Kumita on Dec. 8, 1998, describes an outboard motor mounting. It has a body which is connected to a watercraft mounting bracket by at least one mount. The mount includes a resilient isolating member having a spring constant in a direction parallel to an axis extending from the front to the rear of the motor which is greater than its spring constant in a direction parallel to a second line extending transverse to the first line.

U.S. Pat. No. 6,016,762, which issued to Price on Jan. 25, 2000, describes a planing foil for twin hulled boats. The apparatus is intended for use with a pontoon boat and includes mounting structure for connecting a planing foil to the boat with the foil positioned between and spaced from the pontoon generally amid ship and straddling the transverse centerline of the boat. The foil is also positioned between the water line and the lower surfaces of the pontoon when the boat is at rest so that the foil rises toward a planing position on the surface of the water as the boat is propelled therealong in order to lift the boat and reduce drag.

U.S. Pat. No. 6,302,042, which issued to Biedenweg et al. on Oct. 16, 2001, describes a deck support bracket for a pontoon craft. The device provides a pontoon craft having at least two pontoons, a deck extending between two of the pontoons, an elongate deck support bracket having a second longitudinal slot and attached to a surface of a pontoon at a joint, and an elongate trim member disposed in the second slot, the trim member depending from the second slot and covering the joint, whereby the joint is hidden from view.

U.S. Pat. No. 6,419,534, which issued to Helsel et al. on Jul. 16, 2002, discloses a structural support system for an outboard motor. It uses four connectors attached to a support structure and to an engine system for isolating vibration from being transmitted to the marine vessel to which the outboard is attached. Each connector comprises an elastomeric portion for the purpose of isolating the vibration. Furthermore, the four connectors are disposed in a common plane which is generally perpendicular to a central axis of a driveshaft of the outboard motor. Although precise perpendicularity with the driveshaft axis is not required, it has been determined that if the plane extending through the connectors is within 45 degrees of perpendicularity with the driveshaft axis, improved vibration isolation can be achieved. A support structure, or support saddle, completely surrounds the engine system in the plane of the connectors. All of the support of the outboard motor is provided by the connectors within the plane, with no additional support provided at a lower position on the outboard motor driveshaft housing.

U.S. Pat. No. 6,477,969, which issued to Schell-Tomczak et al. on Nov. 12, 2002, describes a boat with a center pontoon and separate motor mount. The center pontoon provides improved performance and an adjustable engine mount. The adjustable engine mount makes it possible to adjust the relative position of an outboard engine relative to the water line of the boat. The center pontoon includes a relieved top surface for allowing a vertical adjustment movement of the engine mount.

U.S. Pat. No. 6,482,056, which issued to Schell-Tomczak et al. on Nov. 19, 2002, describes an engine mount. The mount makes it possible to adjust the relative position of an outboard engine relative to the water line of a boat. The mount has an elongated, tapered, four-sided body which is attached to the bottom of the hull of the boat by a pair of spaced apart, elongated mounting rails.

U.S. Pat. No. 6,939,184, which issued to Fishburn et al. on Sep. 6, 2005, describes an isolated motor pan for a watercraft. A dampening assembly used in watercraft to isolate the motor from the deck of the watercraft is described. In an embodiment of the invention, a frame including cross-members and a plurality of brackets supports the deck. The dampening assembly extends from the brackets of the frame to the motor and retains the motor at a position ensuring the motor does not contact the frame. The only path available to the vibration generated by the motor is represented by the dampening assemblies that direct the vibrations to the brackets and tubes.

U.S. Pat. No. 7,182,033, which issued to Phillips et al. on Feb. 27, 2007, discloses a self-contained a marine propulsion system for a pontoon boat. The device is disposed within a container, or pod, that is removably attachable to an undersurface of a deck of a pontoon boat. An engine is contained within the container and connected in torque transmitting relation with the marine propulsion device which can be a sterndrive device or a jet drive device. The marine propulsion system is dirigible, with a portion that is rotatable about a generally vertical steering axis and is supported by the container which is attached to the deck of the pontoon boat.

U.S. Pat. No. 7,185,599, which issued to Griffiths et al. on Mar. 6, 2007, discloses a jet drive propulsion system for a pontoon boat. An impeller is driven by an engine. The jet drive propulsion device is dirigible as a result of the fact that a nozzle of the device is rotatable about a generally vertical steering axis. The jet drive device can be supported below a deck of a pontoon boat and located between two flotation tubes of the pontoon boat. Alternative locations can also be used, such as within the structure of the flotation tubes themselves.

The patents described above are hereby expressly incorporated by reference in the description of the present invention.

SUMMARY OF THE INVENTION

A marine propulsion support system made in accordance with a preferred embodiment of the present invention comprises a marine vessel, a propulsion drive mounting transom, and at least one elastomeric support component attached between the marine vessel and the propulsion drive mounting transom. Support of the propulsion drive mounting transom by the marine vessel extends through the at least one elastomeric support component.

In a particularly preferred embodiment of the present invention the marine vessel is a pontoon boat which comprises a deck supported by at least one pontoon. A propulsion drive support structure is attached to the deck and, in a particularly preferred embodiment of the present invention, is supported below the deck. The elastomeric support component is attached between the deck and the propulsion drive support structure in one embodiment of the present invention and is attached between the propulsion drive mounting transom and the propulsion drive support structure in another embodiment of the present invention. A marine propulsion device, such as an outboard motor, is attached to the propulsion drive mounting transom in a preferred embodiment of the present invention. The at least one elastomeric support component comprises four elastomeric mounts in a preferred embodiment of the present invention and each of the elastomeric support components comprises a central metallic member and an outer metallic member in a preferred embodiment of the present invention, wherein a generally annular member is disposed therebetween. The generally annular member is made of an elastomeric material and is attached to both the central and outer metallic members.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully and completely understood from a reading of the description of the preferred embodiment in conjunction with the drawings, in which:

FIG. 1 is intended to illustrate an example that is not considered to be included within preferred embodiments of the present invention;

FIG. 2 is a schematic representation of the type of elastomeric support that is included within the preferred embodiment of the present invention;

FIGS. 3 and 4 are highly schematic representations used to illustrate the functional structure of elastomeric support components used in conjunction with preferred embodiments of the present invention;

FIG. 5 shows an elastomeric mount that can be used in conjunction with the present invention;

FIGS. 6-9 are various illustrations of a first embodiment of the present invention;

FIGS. 10 and 11 show a second embodiment of the present invention; and

FIG. 12 shows a pontoon boat of the type for which the described preferred embodiment of the present invention are intended to be used.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Throughout the description of the preferred embodiment of the present invention, like components will be identified by like reference numerals.

Before describing various embodiments of the present invention, it is important to understand certain meanings of words and terminology that will be used in those descriptions and, just as importantly, it is important to understand certain types of support mounts that are not intended to be included within the scope of the preferred embodiment of the present invention. As an example, FIG. 1 shows an exemplary illustration of two plates, 10 and 12, attached together by fasteners, 14 and 16, with elastomeric material 18 therebetween. This type of connection shown in FIG. 1, with non-elastomeric components, such as the fasteners 14 and 16, directly connected between the two non-elastomeric plates, 10 and 12, is not the type of connection intended to be covered by the present invention. It does not provide sufficiently effective vibration isolation between the two plates 10 and 12, which are typically made of metal or some other non-elastomeric material. Vibration can be transmitted between the plates, 10 and 12, through the attachment components which are rivets in the example shown in FIG. 1, but could be bolts, studs, or other types of attachment mechanisms.

In contradistinction to the arrangement shown in FIG. 1, FIG. 2 provides elastomeric isolation between plates 10 and 12. In the illustration of FIG. 2, a generally cylindrical outer member 22 and a generally cylindrical inner member 24 are arranged in a concentric configuration with an annular elastomeric component 28 disposed therebetween. A plate 12 is attached to the central rod, or inner cylindrical member 24, by bolts 30 or other equivalent mechanisms of attaching these components together. Bolts 34 attach plate 12 to the outer cylindrical portion 22 of the isolation device. All vibrations transmitted by the plate 10 must pass through the elastomeric member 28 before it can be transmitted to the inner cylindrical member 24, or rod. Therefore, between the plate 10 and the plate 12, a vibration isolation structure comprises an elastomeric portion 28 that stands between these components and isolates plates 10 and 12 from each other with regard to vibrations transmitted by plate 10. The arrangement shown in FIG. 2, or functionally equivalent arrangements, is used in a preferred embodiment of the present invention. The phrase “vibration isolation structure” is intended to mean a structure generally similar in function to that shown in FIG. 2 which comprises at least one elastomeric component, such as the annular component 28, that isolates plates 10 and 12 from each other. In addition, the arrangement in FIG. 2 shows a system that does not transmit vibrations between the plates, 10 and 12, other than that which passes through the elastomeric member 28. Support between the plates, 10 and 12, passes through the elastomeric member 28.

FIGS. 3 and 4 show two highly schematic functional representations of structures that fall within the definition of “vibration isolation structure” as used to describe the preferred embodiments of the present invention. It should be understood that both FIGS. 3 and 4 are highly schematic and intended only to show the functional interrelationships between various components. In FIG. 3, the elastomeric support component 40 comprises a central metallic member 42 and an outer metallic member 44 with a generally annular elastomeric member 46 disposed therebetween. The elastomeric support component 40 provides isolation between the central metallic member 42 and the outer metallic member 44. In certain embodiments of the present invention, the central metallic member 42 can be threaded at each end to facilitate attachment to one of the plates described above. The feet 48 facilitate attachment to the other plate. As a result, the annular elastomeric member 46 provides vibration isolation between the two plates which are attached to the central metallic member 42 and the feet 48. FIG. 4 shows an alternative embodiment which is slightly different than that described above in conjunction with FIG. 3. The central metallic member 42 is a cylindrical tube extending through the structure. The outer metallic member 44 is generally similar to that described in FIG. 3. The annular elastomeric member 46 is also generally similar to that described above in conjunction with FIG. 3. To attach the elastomeric support component 40 between the two plates described above, the feet 48 are conventionally attached to one plate and a rod (not shown in FIG. 4) extends through the central opening 49 of the central metallic member 42 and is attached to the other plate.

FIG. 5 shows one type of elastomeric mount which can be used in the embodiments described herein. Although other types of mounts can also be used, the mount illustrated in FIG. 5 has been proven to provide effective isolation when used in conjunction with outboard motors. The type of mount shown in FIG. 5 is generally similar to the type of mount described above in conjunction with U.S. Pat. No. 6,419,534. The advantages of this type of mount are described in detail in that United States patent. In FIG. 5, the central metallic member 42 is provided with a cylindrical opening 49 to receive a bolt or stud extending therethrough and attaching to one of the two plates described above. The feet 48 extend in diametrically opposite directions from the outer metallic member 44. This is different than the illustration shown in FIGS. 3 and 4, but those skilled in the art will recognize that they are functionally similar even though they extend from the outer metallic member 44 in a different manner than those shown in FIGS. 3 and 4. Mounts of the type shown in FIG. 5 will be illustrated in the descriptions of the preferred embodiment below.

FIG. 6 is a side section view of one alternative embodiment of the present invention. A marine vessel 60 is provided with a propulsion drive mounting transom 62 to which a marine propulsion device 63, such as the illustrated outboard motor, is attached. A vibration isolation structure 64 is disposed between the marine vessel 60 and the propulsion drive mounting transom 62. Support of the propulsion drive mounting transom 62 by the marine vessel 60 extends through the vibration isolation structure 64. The vibration isolation structure 64 comprises at least one elastomeric support component 40. In the embodiment of the present invention shown in FIG. 6, a propulsion drive support structure 66 is attached below a deck 68 of the marine vessel 60. As can be seen in FIG. 6, the propulsion drive support structure 66 is rigidly bolted, with bolts 69 to the deck 68. In addition, the vibration isolation structure 64 is located between the propulsion drive support structure 66. Various types of propulsion drive support structures 66 have been referred to, by those skilled in the art, with different names. Structures of this type are referred to as “scoops” in U.S. Pat. No. 2,950,699 and 3,210,783 which are described above. Alternatively, this type of structure is referred to as a “pod” in U.S. Pat. No. 7,182,033 and 7,185,599. The structure identified by reference numeral 66 in FIG. 6 will be referred to as a pod or a propulsion drive support structure in the description of the preferred embodiment of the present invention.

It should be clearly understood that the marine propulsion device 63 most typically will incorporate elastomeric mounts within its structure. This use of elastomeric mounts within outboard motors, for example, is very well known to those skilled in the art and does not directly relate to the benefits of the present invention nor are specific types of these mounts within the structure of the outboard motor required. The present invention is directed to isolate vibrations in the region between the propulsion drive mounting transom 62 and the deck 68 of the marine vessel 60. Vibration isolation within the structure of the outboard motor 63 is not directly related to the present invention nor is it intended to be incorporated within its scope.

With continued reference to FIG. 6, it can be seen that the vibration isolation structure 64 is located proximate the propulsion drive mounting transom 62 rather than more near the deck 68. This is true for the embodiment shown in FIG. 6. The alternative embodiment, which will be described in greater detail below, places the vibration isolation structure 64 closer to the deck 68 than to the propulsion drive mounting transom 62.

FIG. 7 is a view of the propulsion drive mounting transom 62 taken from a position within the pod 66 and facing rearwardly. As can be seen, the elastomeric support components 40 are attached to the propulsion drive mounting transom 62 through the use of the bolts 70 which extend through the central openings of the central metallic members described above in conjunction with FIG. 5. The feet 48 are attached to the pod 66 by bolts 72. Although only four of the bolts 72 are identified in FIG. 7, it should be understood that each of the feet 48 are similarly attached by bolts to the pod 66, or the propulsion drive support structure. FIG. 8 is an isometric view of the pod 66, the propulsion drive mounting transom 62, the elastomeric support component 40 and the marine propulsion device 63 which, in this example, is an outboard motor which is clamped, in a generally conventional manner, to the propulsion drive mounting transom 62. The pod 62 is provided with a plurality of holes 74 that are intended to allow it to be rigidly attached by bolts 69 to deck 68 as illustrated in FIG. 6.

FIG. 9 is an exploded isometric view of the embodiment described above in conjunction with FIGS. 6-8. The pod 66 is shown with the holes 74 intended for rigidly attaching it to the deck of the marine vessel. In addition, holes 79 are intended to allow the elastomeric support components 40 to be attached to the pod 66 by bolts 72 extending through the feet 48. Bolts 78 extend through the propulsion drive mounting transom 62 and through the central opening 49 of the elastomeric support component 40 to allow it to be attached, through the elastomeric portion of the support components 40, to the pod 66. In this way, the propulsion drive mounting transom 62 is supported by the pod, but all vibration emanating from the outboard motor 63 will be damped by its support by the elastomeric portion of the mounts 40.

FIG. 10 illustrates an alternative embodiment of the present invention. The outboard motor 63 is attached to the propulsion drive mounting transom 62 but, in contradistinction to the embodiment described above, the propulsion drive mounting transom 62 can be rigidly attached as a portion of the pod 66, or propulsion drive support structure. The vibration isolation structure in FIG. 10 comprises the four elastomeric support components 40 that are disposed at a location that facilitates the attachment of the pod to the deck.

FIG. 11 illustrates this arrangement with the pod 66 attached to the deck 68. As can be seen in FIG. 11, the vibration isolation structure 64 is located in the region between the pod 66 and the deck 68 rather than the position illustrated in FIG. 6 where the vibration isolation structure 64 is located near the propulsion drive mounting transom 62. Both of these embodiments are within the scope of the present invention and both of them place the vibration isolation structure 64 between the deck 68 and the propulsion drive mounting transom 62.

FIG. 12 is an isometric view of the rear portion of a marine vessel 60 which, in this illustration, is a pontoon boat. Although the concept of the present invention can also be used in conjunction with marine vessels that are not pontoon boats, the preferred embodiments described herein have been developed for use with pontoon boats and, therefore, the specific structures illustrated and described above have been designed for those specific intended applications. In FIG. 12, the marine vessel 60 is provided with two pontoons 84 which support a deck 68 on which a railing structure 86 is provided. The overall structure of the pontoon boat illustrated in FIG. 12 is well known to those skilled in the art and will not be described in greater detail herein. The pod 66, or propulsion drive support structure, is shown suspended below the deck 68 in the manner described above. The marine propulsion device 63, or outboard motor, is supported in a conventional way on the propulsion drive mounting transom 62.

With continued reference to FIGS. 1-12, it can be seen that a marine propulsion support system made in accordance with described embodiments of the present invention comprise a marine vessel 60, a propulsion drive mounting transom 62, and a vibration isolation structure 64 that is disposed between the marine vessel 60 and the propulsion drive mounting transom 62. Support of the propulsion drive mounting transom 62 by the marine vessel 60 extends through the vibration isolation structure 64. The vibration isolation structure 64 comprises at least one elastomeric support component 40. In a particularly preferred embodiment of the present invention, a marine vessel is a pontoon boat which comprises a deck 68 supported by at least one pontoon 84. A propulsion drive support structure 66, or pod, is attached to the deck 68. In one embodiment of the present invention, the propulsion drive support structure 66, or pod, is attached to the deck 68. In one embodiment of the present invention, the propulsion drive support structure 66 is suspended below the deck 68. The vibration isolation structure 64 is disposed between the deck 68 and the propulsion drive support structure 66 in one preferred embodiment of the present invention which is described above in conjunction with FIGS. 10 and 11. Alternatively, the vibration isolation structure 64 can be disposed between the propulsion drive mounting transom 62 and the propulsion drive support structure 66 as described above in conjunction with FIGS. 6-9. In certain embodiments of the present invention, it further comprises a marine propulsion device 63, such as an outboard motor, that is attached to the propulsion drive mounting transom 62. The vibration isolation structure 64, in a particularly preferred embodiment of the present invention, comprises four elastomeric mounts 40. Each of the elastomeric support components 40 comprises a central metallic member 42 and an outer metallic member 44 with a generally annular elastomeric member 46 disposed therebetween.

Although the present invention has been described with particular detail and illustrated to show specific embodiments, it should be understood that alternative embodiments are also within its scope. 

1. A marine propulsion support system, comprising: a marine vessel; a propulsion drive mounting transom; and a vibration isolation structure disposed between said marine vessel and said propulsion drive mounting transom, wherein support of said propulsion drive mounting transom by said marine vessel extends through said vibration isolation structure and wherein said vibration isolation structure comprises at least one elastomeric support component.
 2. The support system of claim 1, wherein: said marine vessel is a pontoon boat.
 3. The support system of claim 2, wherein: said pontoon boat comprises a deck supported by at least one pontoon.
 4. The support system of claim 3, further comprising: a propulsion drive support structure attached to said deck.
 5. The support system of claim 4, wherein: said propulsion drive support structure is suspended below said deck.
 6. The support system of claim 4, wherein: said vibration isolation structure is disposed between said deck and said propulsion drive support structure.
 7. The support system of claim 4, wherein: said vibration isolation structure is disposed between said propulsion drive mounting transom and said propulsion drive support structure.
 8. The support system of claim 1, further comprising: a marine propulsion device attached to said propulsion drive mounting transom.
 9. The support system of claim 1, wherein: said vibration isolation structure comprises four elastomeric mounts.
 10. The support system of claim 1, wherein: said at least one elastomeric support component comprises a central metallic member and an outer metallic member with a generally annular member disposed therebetween.
 11. A marine propulsion support system, comprising: a pontoon boat comprising a deck supported by at least one buoyant pontoon; a propulsion drive mounting transom; and a vibration isolation structure disposed between said pontoon boat and said propulsion drive mounting transom, wherein support of said propulsion drive mounting transom by said marine vessel extends through said vibration isolation structure and wherein said vibration isolation structure comprises at least one elastomeric support component wherein support of said propulsion drive mounting transom by said pontoon boat extends through said vibration isolation structure.
 12. The support system of claim 11, further comprising: a propulsion drive support structure attached to said deck.
 13. The support system of claim 12, wherein: said propulsion drive support structure is suspended below said deck.
 14. The support system of claim 12, wherein: said vibration isolation structure is attached between said deck and said propulsion drive support structure.
 15. The support system of claim 12, wherein: said vibration isolation structure is attached between said propulsion drive mounting transom and said propulsion drive support structure.
 16. The support system of claim 11, further comprising: a marine propulsion device attached to said propulsion drive mounting transom.
 17. A marine propulsion support system, comprising: a pontoon boat; a propulsion drive mounting transom configured to support a marine propulsion device attached to said propulsion drive mounting transom; a deck supported by at least one buoyant pontoon of said pontoon boat; and a vibration isolation structure attached between said pontoon boat and said propulsion drive mounting transom and comprising a plurality of elastomeric support components, wherein support of said propulsion drive mounting transom by said pontoon boat extends through said vibration isolation structure.
 18. The support system of claim 17, further comprising: a propulsion drive support structure supported below said deck, each of said plurality of elastomeric support components comprising a central metallic member and an outer metallic member with a generally annular member disposed therebetween.
 19. The support system of claim 18, wherein: said vibration isolation structure is attached between said deck and said propulsion drive support structure.
 20. The support system of claim 18, wherein: said vibration isolation structure is attached between said propulsion drive mounting transom and said propulsion drive support structure. 